 -- Class: <gtk-button-box>
     Derives from <gtk-box>.

     This class defines the following slots:

     layout-style
          How to layout the buttons in the box. Possible values are default, spread, edge, start and end

 -- Function: gtk-button-box-get-layout (self <gtk-button-box>) =>  (ret <gtk-button-box-style>)
 -- Method: get-layout
     Retrieves the method being used to arrange the buttons in a button box.

     widget
          a <gtk-button-box>.

     ret
          the method used to layout buttons in WIDGET.

 -- Function: gtk-button-box-get-child-secondary (self <gtk-button-box>) (child <gtk-widget>) =>  (ret bool)
 -- Method: get-child-secondary
     Returns whether CHILD should appear in a secondary group of children.

     widget
          a <gtk-button-box>

     child
          a child of WIDGET

     ret
          whether CHILD should appear in a secondary group of children.

     Since 2.4

 -- Function: gtk-button-box-set-layout (self <gtk-button-box>) (layout_style <gtk-button-box-style>)
 -- Method: set-layout
     Changes the way buttons are arranged in their container.

     widget
          a <gtk-button-box>.

     layout-style
          the new layout style.

 -- Function: gtk-button-box-set-child-secondary (self <gtk-button-box>) (child <gtk-widget>) (is_secondary bool)
 -- Method: set-child-secondary
     Sets whether CHILD should appear in a secondary group of children. A typical use of a secondary child is the help button in a dialog.

     This group appears after the other children if the style is GTK_BUTTONBOX_START, GTK_BUTTONBOX_SPREAD or GTK_BUTTONBOX_EDGE, and before the other children if the style is GTK_BUTTONBOX_END. For horizontal button boxes, the definition of before/after depends on direction of the widget (see gtk-widget-set-direction). If the style is GTK_BUTTONBOX_START or GTK_BUTTONBOX_END, then the secondary children are aligned at the other end of the button box from the main children. For the other styles, they appear immediately next to the main children.

     widget
          a <gtk-button-box>

     child
          a child of WIDGET

     is-secondary
          if #t, the CHILD appears in a secondary group of the button box.